Can an honorably discharged use GI Bill?

Of course, one can if they meet the eligibility requirements. See Below.

Montgomery GI Bill Eligibility Details


To be eligible for the Montgomery GI Bill you must meet the following two requirements, no matter when or how you originally become eligible for MGIB. Character of discharge. To use MGIB after you're separated from active duty, your discharge must be fully honorable. Discharges "under honorable conditions" and "general" discharges don't establish eligibility for MGIB.

Important Note: If you weren't eligible previously with your first period of active duty, you may have a second chance by using a later period of active duty.

Completed High School. To use MGIB as an active duty member or after you're separated from active duty, you must obtain a high school diploma or equivalency certificate before you apply for benefits. Completing 12 hours toward a college degree before you apply for benefits also meets this requirement.